For 500+ I still kinda like "Demi-God", nice sound to it. But I think You may already have grabbed that for yourself there Deathrat.
Or how about "Executive Board Memeber"? This is making my head hurt!
This is hard! Well, I'll think of more (better) and get back to you.
Oh, BTW: here are the ones that didn't make my cut: (mostly pretty bad
"Post Master General"
"Senior Rice Eater"
"Has too much free time"
Hey, I said the were bad, didn't I?
I think the intial 5 on the list are just fine. I wouldn't change those at all!